What is a micrometric motorcycle helmet fastener?

The micrometric (or micro ratchet, or plain ratchet) fastener is a relative newcomer to motorcycle crash helmets. It might be new, but it’s a real goodie.

It’s uses a small hard plastic or metal curved strip with teeth on it on one side of the strap. On the other, there’s a corresponding slot with a spring-loaded ratchet mechanism. Insert the strip into the slot and the ratchet grabs onto the teeth, securing the strap.

That means it’s really simple to close and lock micrometric straps; but it’s also easy to open them too. Just pull the red tab connected to the ratchet and it releases the mechanism, unlocking the fastener. Couldn’t be easier.

The strength of a micrometric fastener is in its simplicity to use and, within limits, means that you re-tighten the strap every time. Oh, and in its cheapness to produce.

But it does have a weakness. And that’s in the fact that you only have an inch or so adjustment – the length of the ratchet strip in fact. That’s fine when the strap’s adjusted correctly, but when the strap stretches over time (which it probably will) it’s all too easy to have a micrometric fastener that’s not quite tightened enough.

And that, dear friends, could give you a chance of being one of the 8% of fatal motorcycle accidents where it’s reckoned the helmet comes off!

So, if you ride with a helmet fastened with a micrometric or ratchet strap, if it doesn’t feel tight enough, take a moment to adjust the buckle on the strap itself and not just the micrometric fastener.

Other than that, micrometric’s are great.

Pros of micrometric fasteners

• Really easy to fasten & release
• Safe as houses if adjusted correctly

Cons of micrometric fasteners

• Limited amount of adjustment
• Need periodical strap adjustment

If you’re wanting a micrometric fastener on your new helmet, you can find all our helmets with micrometric fasteners here.